Ratchet mechanism



April l, 1958 H. RElNscH 2,828,647

' RATCHET MECHANISM Filed Dec. 21, 195e /NVE/voz? erker-- Reime/M,-

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RATCHET MECHANISM Herbert Reinsch, Stuttgart, Germany, assigner to Eugen Bauer G. m. b. H., Stuttgart-Unterturkheim, Germany Application December 21, 1956, Seriai No. 629,910

Claims priority, application Germany December 24, 1955 6 Claims. (Ci. 74-576) The present invention relates to a ratchet mechanism and particularly to a ratchet mechanism for winding a spring motor of a motion picture camera.

Ratchet mechanisms according to the prior art have the disadvantage that the pawl rides along the teeth of the ratchet wheel during free turning movement of the latter resulting in a very noisy operation and in excess wear of the teeth and pawl.

lt is an object of the present invention to overcome the disadvantages inherent in the ratchet mechanisms of the prior art.

lt is a further object of the present invention to provide a ratchet mechanism which operates noiseiessly.

With the above objects in view, the present invention mainly consists in a ratchet mechanism comprising a ratchet wheel, a resilient arcuate member embracing and resiliently frictionally engaged with the ratchet wheel for turning therewith, a spring-loaded ratchet pawl movable between a releasing position and a locking position engaging the ratchet wheel and clocking the same against rotation in one direction. The resilient member engages the ratchet pawl while turning with the ratchet wheel in a direction opposite to said one direction for moving the ratchet pawl to the releasing position. Stop means block further turning of the resilient arcuate member in said opposite direction when the ratchet pawl has assumed the releasing position so that further turning of the ratchet wheel resuits in noiseless sliding of the same in the resilient arcuate member whereas turning of the ratchet wheel in said one direction turns the resilient member and moves the same away from the ratchet pawl so as to permit return of the ratchet pawl to the locking position. A

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. l is a side view of one embodiment of the present invention;

Fig. 2 is a view similar to that of Fig. 1 showing the parts in another position;

Fig. 3 is a fragmentary sectional view taken on lines 3 3 of Fig. l; and

Fig. 4 is a side view of a modified embodiment of the present invention.

Referring to the drawing, Fig. 1 shows plate portion 1 of casing means and a shaft 2 turnably mounted in the portion 1 and having one end thereof connected to a handle (not shown) for winding the spring means.

A ratchet wheel 3 is iixedly mounted on the shaft 2 for rotation therewith. A plurality of ratchet teeth 5, located about the periphery of the ratchet wheel 3, are embraced by a resilient arcuate member 7 Which is in resilient frictional engagement therewith. In the embodi- 2,828,647 Patented Apr. 1, 1958 ment illustrated, each of the teeth 5 is formed with an outwardly facing groove 6 in the crown portion 4 thereof, and the resilient arcuate member is located in said groove, as shown in Fig. 3.

The resilient arcuate member 7 extends about the periphery of the ratchet wheel 3 for an angle of at least and advantageously for an angle of 270, leaving free a peripheral portion of the ratchet wheel 3.

In the form of the invention shown particularly in Figs. 1 and 2, a ratchet pawl 11 having inclined guide faces 14, 15 is pivotally connected to the plate portion 1 by connecting pin 10 and is urged against the ratchet wheel 3 by a spring 12 connected to the plate portion 1.

r1`he resilient arcuate member 7 has opposite end portions 8, 13. rThe end portion 13 is located in the recess in pawl 11 formed by the faces 14, 1S and the end portion S, which extends radially outwardly, is spaced from a stop means 9 connected to the portion 1, in the position of the parts as shown in Fig. l.

rThe ratchet pawl 11 blocks turning of the ratchet wheel 3 in one direction, counterclockwise in Figs. l-3. When the ratchet wheel 3 turns in an opposite direction, clockwise in Figs. 1 3, the resilient arcuate member 7 turns therewith in said direction due to the resilient frictional engagement thereof with the ratchet teeth S until further turning of the member 7 is blocked by the stop means 9. During such turning, the end portion 13 is guided along the face 14 of the ratchet pawl 11 so that the latter assumes its releasing position, clear of the ratchet teeth 5, as shown in Fig. 2.

Thus, during turning of the ratchet wheel 3 in said opposite. direction, the ratchet pawl 11 is out of contact therewith. The ratchet wheel 3 slides noiselessly alo-ng the inner surface of the resilient arcuate member 7.

When turning of the ratchet wheel 3 in said opposite direction ceases, the wound spring means turns the ratchet wheel 3 slightly in the counter clockwise direction so that the member 7, turning again with the ratchet wheel 3, permits the ratchet pawl 11 to return to its locking position where it engages a tooth of ratchet wheel 3 and prevents further movement thereof in counterclockwise direction.

The form of the invention shown in Fig. 4 has a resilient arcuate member 19 formed with a radially outwardly extending end portion 20. The resilient means 12 contacts a pivoted ratchet pawl 16 having stop means 13, and adjacent thereto, a guide face 17. The end portion 20 moves along the guide face 17 to the stop means 18 during clockwise rotation of the ratchet wheel 3 to move the pawl 16, against the inuence of the resilient means 12, to its releasing position, as shown in Fig. 4.

In the position of Fig. 4 turning of the ratchet Wheel in clockwise direction will result in sliding of the ratchet wheel along the inner surface of member 19. When the ratchet wheel 3 and the resilient arcuate member 19 cease turning in said clockwise direction and are moved in counterciockwise direction Lby the Wound spring means, the resilient Iarcuate member 19 moves back along the guide face 17 and permits the ratchet pawl 16 to return to its locking position to block further turning of lthe ratchet wheel 3.

The various parts of the ratchet mechanism are advantageously positionally and spatially interrelated so that A soon after turning Iof the ratchet wheel 3 in clockwise tti direction ceases, as illustrated in the drawing.

it will be understood that each of the elements described above, or two or more together,'may also find a useful application in other types of ratchet pawl mechanisms differing from the types described above.

While the invention has been illustrated and described as embodied in a ratchet pawl mechanism including means permitting noiseless turning of the ratchet wheel, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fuily reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specic aspects of this invention and, therefore, such adaptations should and are intended to lbe comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A ratchet mechanism comprising, in combination, 'a ratchet wheel `having ratchet teeth on the periphery thereof and being formed in the crown thereof with a groove; a resilient arcuate member located in said groove and being in resiiient frictional engagement with said ratchet teeth of said ratchet wheel for turning with the same, said member having a pair of opposite end portions spaced from each other a distance greater than the pitch of adjacent teeth; a spring loaded ratchet pawl movabie between a locking position in which said pawl engages one of the teeth of said ratchet wheel between said end portions of said member and blocking the ratchet wheel against rotation in one direction and a releasing position in wh-ich said ratchet pawl is disengaged from said ratchet wheel, said arcuate member engaging said ratchet pawl while turning with said ratchet Wheel in a direction opposite to said one direction for moving said ratchet pawl to said releasing position, while turning of said ratchet wheel in said one direction will turn said arcuate men ber and move the same away from said ratchet pawl so as to permit return of the latter to said locking position; and stop means preventing further turning of said arcuate member in said opposite direction when said ratchet pawi is in said releasing position so that during further turning of said ratchet wheel in said opposite direction said ratchet pawl is held disengaged from sa-id ratchet wheel and clicking noises of said ratchet pawl during turning of said ratchet wheel are prevented.

2. A ratchet mechanism comprising, in combination, a ratchet wheel having ratchet teeth on the periphery thereof and being formed in the crown thereof with a groove; a resilient arcuate member located in said groove and being in resilient frictional engagement with said ratchet teeth of said ratchet wheel for turning with the same, said member having a pair of opposite end portions spaced from each other a distance greater than the pitch of adjacent teeth; a spring loaded ratchet pawl movable be tween a locking position in which said pawl engages one of the teeth of said ratchet wheel between said end portions of said member and blocking the ratchet wheel against rotation in one direct-ion and a releasing position in which said ratchet pawl is disengaged from said ratchet wheel, said arcuate member engaging with one end portion thereof said ratchet pawl while turning with said ratchet wheel in a direction opposite to said one direction for moving said ratchet pawl to said releasing position, while turning of said ratchet wheel in said one direction will turn said arcuate member and move the same away from said ratchet pawl so as to permit return of the latter to said locking position; and stop means preventing further turning of said `arcuate member in said opposite direction when said ratchet pawl is in said releasing position so that during further turning of said ratchet wheel in said opposite direction said ratchet pawl is held disengaged from said ratchet wheel and clicking noises of i said ratchet pawl during turning of said ratchet wheel are prevented.

3. A ratchet mechanism comprising, in combination, a ratchet wheel having ratchet teeth on the periphery thereof and being formed in the crown thereof with a groove having an inner diameter greater than the root diameter of said ratchet teeth; a resiiient arcuate member having an outer diameter greater than the outer diameter of said ratchet wheel and being located in said groove and beinl7 in resilient frictional engagement with said ratchet teeth of said ratchet wheel for turning with the same, said member having a pair of opposite end portions spaced from each other a distance greater than the pitch of adjacent teeth; a spring loaded ratchet pawl movable between a locking position in which said pawl engages one of the teeth of said ratchet wheel between said end portions of said member and blocking the ratchet wheel aga-inst rotation in one direction and a releasing position in which said ratchet pawl is disengaged from said ratchet wheel, said arcuate member engaging with one end portion thereof said ratchet pawl while turning with said ratchet wheel in a direction opposite to said one direction for moving said ratchet pawl to said releasing position, white turning of said ratchet wheel in said one direction will turn said arcuate member and move the same away from said ratchet pawl so as to permit return of the latter to said locking position; and stop means preventing further turning of said arcuate member in said opposite direction when said ratchet pawl is in saidreleasing position so that during further turning of said ratchet wheel in said opposite direction said ratchet pawl is held disengaged from said ratchet wheel and clicking noises of said ratchet pawl during turning of said ratchet wheel are prevented.

4. A ratchet mechanism comprising, in combination, a ratchet wheel having ratchet teeth on the periphery thereof and being formed in the crown thereof with a groove having an inner diameter greater than the root diameter of said ratchet teeth; a resilient arcuate member having an outer diameter greater than the outer diameter of said ratchet wheel and being located in said groove and being in resilient frictional engagement with said ratchet teeth of said ratchet wheel for turning with the same, said member having a pair of opposite end portions spaced from each other a distance greater than the pitch of adjacent teeth; a spring loaded ratchet pawl movable between a locking position in which said pawl engages one of the teeth of said ratchet Wheel between said end portions of said member and blocking the ratchet Wheel against rotation in one direction and a releasing position in which said ratchet pawl is disengaged from said ratchet wheel, said arcuate member engaging with one end portion thereof said ratchet pawl while turning with said ratchet wheel in a direction opposite to sai-d one direction for moving said ratchet pawl to said releasing position, while turning of said ratchet wheel in said one direction will turn said arcuate member and move the same away from said ratchet pawl so as to permit return of the latter to said locking position; and stationary stop means engaging the other of said end portions and preventing further turning of said arcuate member in said opposite direction when said ratchet pawl is in said releasing position so Vthat during further turning of said ratchet wheel in said opposite direction said ratchet pawl is held disengaged from said ratchet Wheel and clicking noises of said ratchet pawl during turning of said ratchet wheel are prevented.

5. A ratchet mechanism comprising, in combination, a ratchet wheel having ratchet teeth on the periphery thereof Vand ybeing formed in the crown thereof with a groove having an inner diameter greater than the root diameter of said ratchet teeth; a resilient arcuate member having an outer diameter greater than vthe outer diameter of said ratchet wheel and being locatedrin said groove and being in resilient frictional engagement with said ratchet teeth of said ratchet wheel for turning with the same, said member having a pair of opposite end portions spaced from each other a distance greater than the pitch of adjacent teeth; a spring loaded ratchet pawl having a cam surface facing the crown of said ratchet wheel and being movable between a locking position in which said pawl engages one of the teeth of said ratchet wheel between said end portions of said member and blocking the ratchet wheel against rotation in one direction and a releasing position in which said ratchet pawl is disengaged from said ratchet wheel, said arcuate member engaging with one end portion thereof said cam surface of said ratchet pawl while turning with said ratchet wheel in a direction opposite to said one direction for moving said ratchet pawl to said releasing position, while turning of said ratchet wheel in said one direction will turn said arcuate member and move the same away from said cam surface of said ratchet pawl so as to permit return of the latter to said locking position; and stop means preventing further turning of said arcuate member in said opposite direction when said ratchet pawl is in said releasing position so that during further turning of said ratchet wheel in said opposite direction said ratchet pawl is held disengaged from said ratchet wheel and clicking noises of said ratchet during turning of said ratchet wheel are prevented.

6. A ratchet mechanism comprising, in combination, a ratchet wheel having ratchet teeth on the periphery thereof and being formed in the crown thereof with a groove having an inner diameter greater than the root diameter of said ratchet teeth; a resilient arcuate member having an outer diameter greater than the outer diameter of said ratchet wheel and being located in said groove and being in resilient frictional engagement with said ratchet teeth of said ratchet wheel for turning with the same, said member having a pair of opposite end portions spaced from each other a distance greater than the pitch of adjacent teeth; a spring loaded ratchet pawl having a cam surface facing the crown of said ratchet wheel and being movable between a locking position in which said pawl engages one of the teeth of said ratchet wheel between said end portions of said member and blocking the ratchet wheel against rotation in one direction and a releasing position in which said ratchet pawl is disengaged from said ratchet wheel, said arcuate member engaging with one end portion thereof said cam surface of said ratchet pawl while turning with said ratchet wheel in a direction opposite to said one direction for moving said ratchet pawl to said releasing position, while turning of said ratchet wheel in said one direction will turn said arcuate member and move the same away from said cam surface of said ratchet pawl so as to permit return of the latter to said locking position; and stop means formed by a shoulder in said cam surface and preventing further turning of said arcuate member in said opposite direction when said ratchet pawl is in said releasing position so that during further turning of said ratchet wheel in said opposite direction said ratchet pawl is held disengaged from said ratchet wheel and clicking noises of said ratchet during turning of said ratchet Wheel are prevented.

References Cited in the le of this patent UNITED STATES PATENTS 141,367 Manson July 29, 1873 933,866 Weickel et al. Sept. 14, 1909 1,057,598 Van Der Weri Apr. 1, 1918 1,150,587 Falkenan Aug. 17, 1915 2,354,530 McMahon July 25, 1944 2,522,004 Weidenman Sept. 12, 1950 

